General information
With its relatively short distance between the bow and stern of two vessels, tandem offloading always has been considered as an complex operation. Taking into account that in collinear wind, waves and current ‘fish-tailing’ can occur and that in non-collinear environments the mean heading of the two vessels can be different due to their difference in draft, this operation needs careful consideration. Nowadays, tandem offloading is performed with a passive bow hawser mooring from trading tankers and with dedicated DP shuttle tankers. In mild environments, tandem offloading is also applied for the offloading from spread moored FPSOs. Especially in this situation it is very important to take into account the possibility of sudden changes in the environment, such as wind squalls and tide-rips (changes of current direction).
With its relatively short distance between the bow and stern of two vessels, tandem offloading always has been considered as an complex operation. Taking into account that in collinear wind, waves and current ‘fish-tailing’ can occur and that in non-collinear environments the mean heading of the two vessels can be different due to their difference in draft, this operation needs careful consideration. Nowadays, tandem offloading is performed with a passive bow hawser mooring from trading tankers and with dedicated DP shuttle tankers. In mild environments, tandem offloading is also applied for the offloading from spread moored FPSOs. Especially in this situation it is very important to take into account the possibility of sudden changes in the environment, such as wind squalls and tide-rips (changes of current direction).
Services & Activities
The Offshore Department has a lot of experience in the testing and numerical modelling of tandem offloading operations, it is almost standard for each FPSO project. Recently, as part of the ‘Offloading Operability’ JIP, the SHUTTLE program has been developed, which can simulate tandem offloading operations, including the wind, wave and current interaction effects between the two vessels. This dedicated tool can be applied for our clients.
The Trials and Monitoring Department can be involved in full-scale measurement of tandem offloading operations.
The Offshore Department has a lot of experience in the testing and numerical modelling of tandem offloading operations, it is almost standard for each FPSO project. Recently, as part of the ‘Offloading Operability’ JIP, the SHUTTLE program has been developed, which can simulate tandem offloading operations, including the wind, wave and current interaction effects between the two vessels. This dedicated tool can be applied for our clients.
The Trials and Monitoring Department can be involved in full-scale measurement of tandem offloading operations.
Facilities & Tools
Tandem offloading model tests are carried out in the following MARIN facilities :
Tandem offloading model tests are carried out in the following MARIN facilities :
- Offshore Basin: DP model tests in combined current, waves and wind
The following tools are used to study tandem offloading :
DIFFRAC: 3-D potential theory including wave diffraction
DRIFTP/DBDRIFT: Second order wave excited (drift) forces
LIFSIM/LIFMOT: Analysis of multi body dyamics and lift operations
DRIFTP/DBDRIFT: Second order wave excited (drift) forces
LIFSIM/LIFMOT: Analysis of multi body dyamics and lift operations
Software Sales
Some software tools are available for commercial use outside MARIN. A complete overview of these software tools for sale can be found under Software Sales.
Some software tools are available for commercial use outside MARIN. A complete overview of these software tools for sale can be found under Software Sales.
Experience
The list below gives a review of tandem offloading projects carried out at MARIN:
The list below gives a review of tandem offloading projects carried out at MARIN:
- Shell LNG FPSO development: tandem offloading tests (Shell, 2002)
- Azure LNG FPSO development (BV, 2000)
- Chevron tandem offloading / fishtailing mitigation study (Chevron, 2000)
- Shell Soroosh tandem offloading tests (London Marine Consultants, 2000)
- JIP ‘Offshore LNG offloading System’ (FMC, 1998)
- Girassol tandem tests (ELF, 1998)
- Spread moored Bonga FPSO tandem simulations (Shell, 1998)
- Campeche model tests (PEMEX, 1998)
- Marlim field FPSO (Petrobras, 1997)
- Shell Maui Bay FPSO (Sofec, 1995)
- Escravos FPSO (Chevron, 1995)
- Fife field FPSO (Bluewater, 1994)
- BHP Liverpool Bay model tests for shuttle size optimisation (BHP, 1994)
- Griffin, Jabiru, Challis and Skua tandem tests (BHP, to 1993)
The following Joint Industry Projects (JIPs) were focussed on tandem offloading:
- Offloading Operability (development of SHUTTLE)
Most recent tandem offloading papers presented by MARIN
(complete overview of papers can be found under Publications)
(complete overview of papers can be found under Publications)
Predicting Wind Loads For FPSO Tandem Offloading Using CFD
Koop, A.H., Klaij, C.M. and Vaz, G.N.V.B., OMAE ASME 29th International Conference on Ocean, Offshore and Arctic Engineering, Shanghai, 2010
A New Method to Optimise the Operability of Deepwater Offloading Operations
Hielke Brugts (Bluewater Energy Services), Jos van Doorn, Tim Bunnik and Bas Buchner (MARIN), Deep Offshore Technology Conference (DOT), Vitoria, 2005
F(P)SO Offloading Concepts, their Nautical Feasibility and Safety Assessment
J.T.M. van Doorn and D. ten Hove (MARIN), Offshore Technology Conference (OTC), Houston, 2002
Low-Frequency Motions of Tankers on Tandem Offloading Condition
G.J. Feikema, R.H.M. Huijsmans, and A.B. Aalbers, Offshore Technology Conference (OTC), Houston, 1992
Koop, A.H., Klaij, C.M. and Vaz, G.N.V.B., OMAE ASME 29th International Conference on Ocean, Offshore and Arctic Engineering, Shanghai, 2010
A New Method to Optimise the Operability of Deepwater Offloading Operations
Hielke Brugts (Bluewater Energy Services), Jos van Doorn, Tim Bunnik and Bas Buchner (MARIN), Deep Offshore Technology Conference (DOT), Vitoria, 2005
F(P)SO Offloading Concepts, their Nautical Feasibility and Safety Assessment
J.T.M. van Doorn and D. ten Hove (MARIN), Offshore Technology Conference (OTC), Houston, 2002
Low-Frequency Motions of Tankers on Tandem Offloading Condition
G.J. Feikema, R.H.M. Huijsmans, and A.B. Aalbers, Offshore Technology Conference (OTC), Houston, 1992
Most recent tandem offloading articles written for MARIN Report
(complete overview of articles can be found under Publications)
(complete overview of articles can be found under Publications)
Bridge simulator training for the Munin FPSO
Bluewater recently started operating the Munin FPSO at the Huizhou 21-1 Field in the South China Sea, after the field’s permanent FPSO suffered Typhoon damage. MARIN provided Bridge Simulation training and once again, this...
CFD for offshore applications
In 2009, MARIN took a major step towards the commercial application of Computational Fluid Dynamics (CFD) tools for offshore-related problems. This article outlines achievements so far and the problems currently under...
Tandem offloading of LNG by means of DP
Recently, SBM commissioned MARIN to perform model tests to investigate the feasibility of tandem offloading of LNG from an LNG FPSO to an LNG shuttle tanker. The carrier was kept in position by a full DP system and follows...
MARIN and Oceânica work in tandem on project
MARIN and Oceânica recently joined forces to study the tandem offloading operation of the first FPSO in the Gulf of Mexico for the Petrobras Cascade/Chinook development. MARIN performed the model tests in its deepwater...
2009: The year of LNG
Liquefied Natural Gas (LNG) has become the fastest growing sector of the world’s gas market. With many large LNG offloading projects planned this year in the Offshore Basin, 2009 can be proudly proclaimed “The year of LNG”....
Bluewater recently started operating the Munin FPSO at the Huizhou 21-1 Field in the South China Sea, after the field’s permanent FPSO suffered Typhoon damage. MARIN provided Bridge Simulation training and once again, this...
CFD for offshore applications
In 2009, MARIN took a major step towards the commercial application of Computational Fluid Dynamics (CFD) tools for offshore-related problems. This article outlines achievements so far and the problems currently under...
Tandem offloading of LNG by means of DP
Recently, SBM commissioned MARIN to perform model tests to investigate the feasibility of tandem offloading of LNG from an LNG FPSO to an LNG shuttle tanker. The carrier was kept in position by a full DP system and follows...
MARIN and Oceânica work in tandem on project
MARIN and Oceânica recently joined forces to study the tandem offloading operation of the first FPSO in the Gulf of Mexico for the Petrobras Cascade/Chinook development. MARIN performed the model tests in its deepwater...
2009: The year of LNG
Liquefied Natural Gas (LNG) has become the fastest growing sector of the world’s gas market. With many large LNG offloading projects planned this year in the Offshore Basin, 2009 can be proudly proclaimed “The year of LNG”....
Contact
For more information on how MARIN can help your organisation with the issue of tandem offloading, please contact:
For model test and simulation activities: Offshore Department
For nautical training: MSCN
For full-scale measurements: the Trials and Monitoring Department
For more information on how MARIN can help your organisation with the issue of tandem offloading, please contact:
For model test and simulation activities: Offshore Department
For nautical training: MSCN
For full-scale measurements: the Trials and Monitoring Department